@mixin bg-rgba_000( $opacity: .6 ) {
  background-color: rgba(0,0,0,$opacity);
}

@mixin min-screen( $width ) {
   @media screen and ( min-width: $width ) {
     @content;
   }
}

@mixin max-screen( $width ) {
   @media screen and ( max-width: $width ) {
     @content;
   }
}
